Hydropneumatic Braking and Return System for Barrel-Recoil Guns

ABSTRACT

The invention relates to a hydropneumatic braking and return system for barrel-recoil guns having at least one working cylinder ( 1 ) which can be arranged between the gun barrel ( 6 ) of the gun and that mass ( 7 ) of the gun which does not recoil, contains a brake fluid ( 4 ) and has displaceable working pistons ( 3 ) which are arranged on a piston rod ( 2 ). In order to obtain a braking and return system of simple construction for barrel-recoil guns, with which it is simply possible, moreover, to take changes in different shooting parameters into consideration, the invention proposes to replace the braking cylinder of known systems with a simple working cylinder ( 1 ) having a working piston ( 3 ), wherein the working cylinder ( 1 ) is connected to a hydraulic accumulator ( 9 ) via a separate controllable pressure relief valve ( 10 ), wherein the pressure relief valve ( 10 ) can preferably be actuated in such a way that a substantially constant brake-force profile results during the recoil of the corresponding gun barrel ( 6 ).

The invention relates to a hydropneumatic braking and return system for barrel-recoil guns.

In barrel-recoil guns, the recoiling gun barrel is braked after firing generally by a hydraulic barrel brake (cf. for example Rheinmetall “Waffentechnisches Taschenbuch”, 7^(th) edition 1985 pages 440 ff.). In this case, a piston, which is connected to the recoiling mass of the gun, is displaced in a fluid-filled brake cylinder and the fluid which is displaced during the recoil is pressed through a narrow throughflow cross section of the piston or of the cylinder wall adjoining the piston. After completion of the recoil, the recoiling mass is then pressed back again to the starting position with the aid of a separate barrel returner. The barrel returner is conventionally configured as a pneumatic, hydropneumatic or mechanical system.

Drawbacks of the known systems consisting of a hydraulic barrel brake and barrel returner include the fact that they are mechanically highly complex in their construction. In order for example to obtain, despite the varying recoil speed of the gun barrel, a constant brake force profile which is required in barrel brakes, the throughflow cross section is varied as a function of distance in the known barrel brakes. This takes place, for example, through an annular gap between the piston rod, which is hollow in its configuration, and a stationary control rod having an axially varying diameter.

In addition, in the known barrel brake and barrel returner systems, varying shooting parameters, such as the different pressure curves when different types of ammunition are used, generally cannot easily be taken into account. On the contrary, these cases each require complex adjustment tests or if appropriate even the barrel brakes or barrel returners to be replaced.

It is already known from DE 198 32 495 C1 to use, in a hydrodynamic gun damper having a fluid flow control rod, such as is described in greater detail in DE 38 24 153 A1, a magnetorheological or electrorheological damping medium, the viscosity of which can be varied by a corresponding control device, in order to take account of the braking behavior of barrel brakes as a function of the various shooting parameters such as the type of ammunition, the type of propellant, the elevation of the barrel, the running direction of the barrel and temperature of the damping medium.

Nevertheless, in this known barrel brake too, a relatively complex mechanical construction of the barrel brake is required in order to realize a throughflow cross section which is dependent on the recoil path.

The invention is based on the object of disclosing a braking and return system for barrel-recoil guns, which system is mechanically much simpler in its construction than comparable known systems and which allows changes in different shooting parameters to be taken into account in a simple manner without it being essential to alter the viscosity of the brake fluid for this purpose.

According to the invention, this object is achieved by the features of claim 1. The sub-claims disclose further, particularly advantageous configurations of the invention.

The invention is based substantially on the notion of dispensing with a specific brake cylinder having a control rod for defining a throughflow cross section which is dependent on the recoil path and of replacing the brake cylinder with a simple working cylinder having a conventional working piston, the working cylinder being connected to a hydraulic accumulator via an external pressure limiting valve and a hydraulic control circuit. In this case, the pressure limiting valve can be set manually to fixed values or can be operated for example electronically/electrically from a controller in such a way that preferably a substantially constant brake force profile results during the recoil of the gun barrel.

The hydraulic accumulator comprises a hydraulic cylinder in which a separating piston separates a first chamber, which is connected to the pressure limiting valve, from a second chamber, which is filled with a prestressed gas, in such a way that during the recoil movement of the gun barrel from its rest position to its recoil end position, the displacement of the working piston presses the displaced brake fluid from the working cylinder into the first chamber via the adjustable pressure limiting valve and the gas in the second chamber of the hydraulic accumulator is compressed as a result of displacement of the separating piston. During relaxation of the compressed gas, the brake fluid is then pressed back into the working cylinder and causes the gun barrel to advance to its rest position, thus obviating the need for a separate barrel returner.

Preferably, the hydraulic control circuit comprises, in addition to the pressure limiting valve, inter alia at least one throttle valve with which the speed of the flow of brake fluid which is pressed back from the first chamber of the hydraulic accumulator into the working cylinder can be varied in a predefinable manner.

In the system according to the invention, the working cylinder and the working piston therefore serve both as the barrel brake and as the barrel returner and heat compensating system. Both the braking behavior and the speed of advance and the advance braking can be controlled manually by the hydraulic control circuit and/or automatically by a corresponding control device, so that the system can easily be adapted inter alia also to different types of ammunition.

As a result of the fact that a control rod and the mechanical recoil path adjustment mechanism are dispensed with in the brake cylinder, there is also no need for the complex adjustment tests which are required in known comparable barrel brakes and with which the sufficiently precise control profile and also the preliminary computer design of the corresponding control profile are found for the first time.

In addition, the system according to the invention has the advantage that the working cylinder can be configured so as to be much smaller and lighter than conventional brake cylinders. It is therefore possible to integrate a plurality of working cylinders into a weapon system in order to achieve more beneficial force profiles in the force-diverting components. In this case, the working cylinders can for example be arranged concentrically around the gun barrel.

The hydraulic control circuit can be mounted on the gun. However, it can for example also be arranged on or in the vehicle carrying the gun. This can yield inter alia advantages with regard to safety, the distribution of mass, maintenance and upkeep.

Preferably, the system according to the invention is of modular construction, so that it can be used in a plurality of types of weapon and an individual design (each weapon having its own barrel brake) can be dispensed with. This offers inter alia advantages in the logistics, development and certification of the system according to the invention.

Unlike in known barrel brakes, in which, when the brake fluid is changed, the change in density (and the thus altered control profile) generally means that the control rod has to be changed, this is not required in the system according to the invention. On the contrary, in the system according to the invention, merely the activation of the pressure limiting valve is altered when the brake fluid is changed. This can take place for example as a result of altered software of the electronic control device activating the pressure limiting valve. The pressure limiting valve is preferably always set to a specific pressure (opening pressure). This can take place once from the max. system pressure. This leads to different recoil paths for different shot parameters (for example the size of the propellant, type of bullets, elevation of the barrel). Alternatively, adjustment immediately before each shot is possible. This allows the corresponding value for the opening pressure of the valve to be set depending on the ammunition selected. This value should preferably have been determined beforehand. However, the entire recoil path can be utilized in this case too and pressures which are as small as possible are obtained.

If required, the hydraulic control circuit can additionally also contain a cooling system, for example a heat exchanger, for cooling the brake fluid which is heated during the recoil and advance of the gun barrel.

Further details and advantages of the invention will emerge from the following exemplary embodiment described with reference to a FIGURE.

In the FIGURE, reference numeral 1 denotes a working cylinder comprising a working piston 3 fastened to a piston rod 2. A brake fluid 4 (for example oil) is contained in the working cylinder 1. The piston rod 2 is connected, on its end remote from the working piston 3, to the base piece 5 of a gun barrel 6 indicated by broken lines (recoiling mass of the gun) and the working cylinder 1 to a cradle 7, also indicated by broken lines, of the corresponding gun (non-recoiling mass).

The working cylinder 1 is connected to a hydraulic accumulator 9 via a hydraulic control circuit 8 which is indicated merely schematically. In this case, the control circuit 8 comprises a pressure limiting valve 10 which can be controlled or regulated by an electronic control device 11. The electronic control device can for example be the fire control computer of the corresponding weapon system.

The hydraulic accumulator 9 comprises a hydraulic cylinder 12 in which a separating piston 13 separates a first chamber 14, which is connected to the hydraulic control circuit 8, from a second chamber 16, which is filled with a prestressed gas 15 (for example nitrogen).

During firing, the gun barrel 6 recoils from its rest position illustrated in the FIGURE to its recoil end position in the direction of the arrow 17. In this case, the working piston 3 is also displaced in the direction of the arrow 17 and the brake fluid 4 thus displaced is pressed by the working cylinder 1 into the first chamber 14 of the hydraulic accumulator 9 via the adjustable pressure limiting valve 10, at which the back pressure is produced, of the hydraulic control circuit 8. This causes a displacement of the separating piston 13, so that the gas 15 in the second chamber 16 of the hydraulic accumulator 9 is compressed until the gun barrel 6 has reached its recoil end position.

After reaching the recoil end position of the gun barrel 6, the gas 15 relaxes again and displaces the separating piston 13 until the gas 15 has relaxed to its initial pressure. As a result of displacement of the separating piston 13, the brake fluid 4 is pressed back out of the first chamber 14 of the hydraulic accumulator 9 into the working cylinder 1 and the gun barrel 6 is caused to advance to its rest position. In this case, the speed of advance can be controlled or regulated manually using a throttle valve 18 provided in the hydraulic control circuit 8 or by means of the electronic control device 11.

A directional control valve which may be seen in the figure and is denoted by reference numeral 19 is switched for the most part only for the advance of the barrel. Beforehand, it prevents brake oil from flowing away via the throttle 18. The throttle valve 18 is closed in its basic position and is then opened if the brake pressure exceeds the system pressure (pressure accumulator pressure).

If a plurality of working cylinders are used, the following variants are alternatively possible: a plurality of working cylinders and also one accumulator and one circuit, or a plurality of working cylinders, a plurality of accumulators and one circuit, or a plurality of working cylinders, accumulators pertaining thereto and the associated circuit (as a unit=brake return module).

The invention is obviously not limited to the exemplary embodiment described hereinbefore. Thus, the hydraulic control circuit can for example additionally contain also a cooling system, for example a heat exchanger, for cooling the brake fluid which is heated during the recoil and advance of the gun barrel. In this case, the cooler, which will not be described in greater detail, should preferably be incorporated into the line in which the lowest pressure occurs (for example the current regulator line), so as to minimize the size of the cooler.

In addition, the working cylinder can be provided both with a “pulling” and with a “pressing” piston rod.

Furthermore, the pressure limiting valve does not necessarily have to be activated in such a way as to produce a constant brake force profile but rather, if desired, almost any brake force profile can be generated by appropriate activation of the pressure limiting valve. 

1-6. (canceled)
 7. A hydropneumatic braking and return system for a barrel-recoil gun, comprising: at least one working cylinder arrangeable between a gun barrel of the gun and a mass of the gun that does not recoil, the cylinder including a displaceable working piston arranged on a piston rod, and containing brake fluid; a hydraulic accumulator; and a hydraulic control circuit including an adjustable pressure limiting valve, the working cylinder connected to the hydraulic accumulator via the adjustable pressure limiting valve of the hydraulic control circuit, the hydraulic accumulator including a hydraulic cylinder in which a separating piston separates a first chamber, which is connected to the hydraulic control circuit, from a second chamber, which is filled with a prestressed gas, so that during a recoil movement of the gun barrel from a rest position to a recoil end position, the displacement of the working piston presses brake fluid from the working cylinder into the first chamber of the hydraulic cylinder via the adjustable pressure limiting valve and the gas in the second chamber of the hydraulic accumulator is compressed as a result of displacement of the separating piston, the brake fluid being pressed back into the working cylinder upon relaxation of the compressed gas thereby causing the gun barrel to advance to its rest position.
 8. The hydropneumatic braking and return system according to claim 7, wherein the hydraulic control circuit contains at least one throttle valve with which the speed of a flow of brake fluid which is pressed back from the first chamber of the hydraulic accumulator into the working cylinder is variable in a predefinable manner.
 9. The hydropneumatic braking and return system according to claim 7, wherein the hydraulic control circuit includes a cooling system.
 10. The hydropneumatic braking and return system according to claim 7, wherein a plurality of the working cylinders are arranged as to be distributed uniformly around a circumference of the gun barrel.
 11. The hydropneumatic braking and return system according to claim 7, and further comprising a central electronic control device operatively arranged so as to activate the actuators of the hydraulic control circuit.
 12. The hydropneumatic braking and return system according to claim 11, wherein the electronic control device is operative to activate the pressure limiting valve so that a substantially constant brake force profile results during the recoil of the gun barrel. 